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| | <SX load='3j4s' size='340' side='right' viewer='molstar' caption='[[3j4s]], [[Resolution|resolution]] 6.80Å' scene=''> | | <SX load='3j4s' size='340' side='right' viewer='molstar' caption='[[3j4s]], [[Resolution|resolution]] 6.80Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[3j4s]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacti Bacti]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J4S OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3J4S FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[3j4s]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_thuringiensis_serovar_israelensis Bacillus thuringiensis serovar israelensis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3J4S OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3J4S FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 6.8Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">pBt156 ([https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1430 BACTI])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GDP:GUANOSINE-5-DIPHOSPHATE'>GDP</scene></td></tr> |
| | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3j4s FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j4s OCA], [https://pdbe.org/3j4s PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3j4s RCSB], [https://www.ebi.ac.uk/pdbsum/3j4s PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3j4s ProSAT]</span></td></tr> | | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3j4s FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3j4s OCA], [https://pdbe.org/3j4s PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3j4s RCSB], [https://www.ebi.ac.uk/pdbsum/3j4s PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3j4s ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/TUBZ_BACTI TUBZ_BACTI] A tubulin-like, filament forming GTPase; the motor component of the type III plasmid partition system which ensures correct segregation of the pBtoxis plasmid. Filaments may seed from the centromere-like site (tubC) when bound by DNA-binding protein TubR; the tubC-TubR complex stabilizes the TubZ filament. Filaments grow at the plus end and depolymerize at the minus end, a process called treadmilling. TubR-tubC complexes track the depolymerizing minus end of the filament, probably pulling plasmid within the cell (PubMed:20534443, PubMed:23010931, PubMed:25825718). Required for pBtoxis plasmid replication/partition (PubMed:16936050, PubMed:17873046). Binds the TubR-tubC complex; GTP is not required for binding to TubR-tubC. TubZ alone does not bind DNA (PubMed:17873046, PubMed:20534443, PubMed:25825718). Has a high GTPase activity in the presence of Mg(2+); in the presence of GTP assembles into dynamic filaments which upon polymerization bind almost exclusively GDP. Filament formation is cooperative, requiring a critical concentration. Formation occurs very quickly and is followed by disassembly as GTP is consumed (PubMed:18198178).<ref>PMID:16936050</ref> <ref>PMID:17873046</ref> <ref>PMID:18198178</ref> <ref>PMID:20534443</ref> <ref>PMID:23010931</ref> <ref>PMID:25825718</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | __TOC__ | | __TOC__ |
| | </SX> | | </SX> |
| - | [[Category: Bacti]] | + | [[Category: Bacillus thuringiensis serovar israelensis]] |
| | [[Category: Large Structures]] | | [[Category: Large Structures]] |
| - | [[Category: Agard, D A]] | + | [[Category: Agard DA]] |
| - | [[Category: Montabana, E A]] | + | [[Category: Montabana EA]] |
| - | [[Category: Ftsz-like]]
| + | |
| - | [[Category: Gtpase]]
| + | |
| - | [[Category: Structural protein]]
| + | |
| - | [[Category: Tubulin-like]]
| + | |
| Structural highlights
Function
TUBZ_BACTI A tubulin-like, filament forming GTPase; the motor component of the type III plasmid partition system which ensures correct segregation of the pBtoxis plasmid. Filaments may seed from the centromere-like site (tubC) when bound by DNA-binding protein TubR; the tubC-TubR complex stabilizes the TubZ filament. Filaments grow at the plus end and depolymerize at the minus end, a process called treadmilling. TubR-tubC complexes track the depolymerizing minus end of the filament, probably pulling plasmid within the cell (PubMed:20534443, PubMed:23010931, PubMed:25825718). Required for pBtoxis plasmid replication/partition (PubMed:16936050, PubMed:17873046). Binds the TubR-tubC complex; GTP is not required for binding to TubR-tubC. TubZ alone does not bind DNA (PubMed:17873046, PubMed:20534443, PubMed:25825718). Has a high GTPase activity in the presence of Mg(2+); in the presence of GTP assembles into dynamic filaments which upon polymerization bind almost exclusively GDP. Filament formation is cooperative, requiring a critical concentration. Formation occurs very quickly and is followed by disassembly as GTP is consumed (PubMed:18198178).[1] [2] [3] [4] [5] [6]
Publication Abstract from PubMed
Cytoskeletal filaments form diverse superstructures that are highly adapted for specific functions. The recently discovered TubZ subfamily of tubulins is involved in type III plasmid partitioning systems, facilitating faithful segregation of low copy-number plasmids during bacterial cell division. One such protein, TubZ-Bt, is found on the large pBtoxis plasmid in Bacillus thuringiensis, and interacts via its extended C terminus with a DNA adaptor protein TubR. Here, we use cryo-electron microscopy to determine the structure of TubZ-Bt filaments and light scattering to explore their mechanism of polymerization. Surprisingly, we find that the helical filament architecture is remarkably sensitive to nucleotide state, changing from two-stranded to four-stranded depending on the ability of TubZ-Bt to hydrolyze GTP. We present pseudoatomic models of both the two- and four-protofilament forms based on cryo-electron microscopy reconstructions (10.8 A and 6.9 A, respectively) of filaments formed under different nucleotide states. These data lead to a model in which the two-stranded filament is a necessary intermediate along the pathway to formation of the four-stranded filament. Such nucleotide-directed structural polymorphism is to our knowledge an unprecedented mechanism for the formation of polar filaments.
Bacterial tubulin TubZ-Bt transitions between a two-stranded intermediate and a four-stranded filament upon GTP hydrolysis.,Montabana EA, Agard DA Proc Natl Acad Sci U S A. 2014 Mar 4;111(9):3407-12. doi:, 10.1073/pnas.1318339111. Epub 2014 Feb 18. PMID:24550513[7]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Tang M, Bideshi DK, Park HW, Federici BA. Minireplicon from pBtoxis of Bacillus thuringiensis subsp. israelensis. Appl Environ Microbiol. 2006 Nov;72(11):6948-54. PMID:16936050 doi:10.1128/AEM.00976-06
- ↑ Tang M, Bideshi DK, Park HW, Federici BA. Iteron-binding ORF157 and FtsZ-like ORF156 proteins encoded by pBtoxis play a role in its replication in Bacillus thuringiensis subsp. israelensis. J Bacteriol. 2007 Nov;189(22):8053-8. PMID:17873046 doi:10.1128/JB.00908-07
- ↑ Chen Y, Erickson HP. In vitro assembly studies of FtsZ/tubulin-like proteins (TubZ) from Bacillus plasmids: evidence for a capping mechanism. J Biol Chem. 2008 Mar 28;283(13):8102-9. PMID:18198178 doi:10.1074/jbc.M709163200
- ↑ Ni L, Xu W, Kumaraswami M, Schumacher MA. Plasmid protein TubR uses a distinct mode of HTH-DNA binding and recruits the prokaryotic tubulin homolog TubZ to effect DNA partition. Proc Natl Acad Sci U S A. 2010 Jun 4. PMID:20534443
- ↑ Aylett CH, Lowe J. Superstructure of the centromeric complex of TubZRC plasmid partitioning systems. Proc Natl Acad Sci U S A. 2012 Oct 9;109(41):16522-7. doi:, 10.1073/pnas.1210899109. Epub 2012 Sep 25. PMID:23010931 doi:http://dx.doi.org/10.1073/pnas.1210899109
- ↑ Fink G, Löwe J. Reconstitution of a prokaryotic minus end-tracking system using TubRC centromeric complexes and tubulin-like protein TubZ filaments. Proc Natl Acad Sci U S A. 2015 Apr 14;112(15):E1845-50. PMID:25825718 doi:10.1073/pnas.1423746112
- ↑ Montabana EA, Agard DA. Bacterial tubulin TubZ-Bt transitions between a two-stranded intermediate and a four-stranded filament upon GTP hydrolysis. Proc Natl Acad Sci U S A. 2014 Mar 4;111(9):3407-12. doi:, 10.1073/pnas.1318339111. Epub 2014 Feb 18. PMID:24550513 doi:http://dx.doi.org/10.1073/pnas.1318339111
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